The Antarctic Coastal Current in the Bellingshausen Sea

The ice shelves of the West Antarctic Ice Sheet experience basal melting induced by underlying warm, salty Circumpolar DeepWater. Basal meltwater, along with runoff from ice sheets, supplies fresh buoyant water to a circulation feature near the coast, the Antarctic Coastal Current (AACC). The formation, structure, and coherence of the AACC has been well documented along the West Antarctic Peninsula (WAP). Observations from instrumented seals collected in the Bellingshausen Sea offer extensive hydrographic coverage throughout the year, providing evidence of the continuation of the westward flowing AACC from the WAP towards the Amundsen Sea. The observations reported here demonstrate that the coastal boundary current enters the eastern Bellingshausen Sea from the WAP and flows westward along the face of multiple ice shelves, including the westernmost Abbot Ice Shelf. The presence of the AACC in the western Bellingshausen Sea has implications for the export of water properties into the eastern Amundsen Sea, which we suggest may occur through multiple pathways, either along the coast or along the continental shelf break. The temperature, salinity, and density structure of the current indicates an increase in baroclinic transport as the AACC flows from the east to the west, and as it entrains meltwater from the ice shelves in the Bellingshausen Sea. The AACC acts as a mechanism to transport meltwater out of the Bellingshausen Sea and into the Amundsen and Ross seas, with the potential to impact, respectively, basal melt rates and bottom water formation in these regions.

Automated summary

The West Antarctic Ice Sheet experiences basal melting induced by warm, salty Circumpolar Deep Water, resulting in the formation of the Antarctic Coastal Current (AACC). The AACC flows westward from the West Antarctic Peninsula towards the Bellingshausen Sea, impacting the export of water properties into the eastern Amundsen Sea. This current transports meltwater out of the Bellingshausen Sea and into the Amundsen and Ross seas, potentially affecting basal melt rates and bottom water formation in these regions.